### Diffraction Elastic Constants for Arbitrary Aggregates

- Thomas Gnaupel-Herold
- MSEL

X-ray and neutron diffraction are among the most important
techniques for nondestructive evaluation of stress. Diffraction
elastic constants are necessary to translate lattice strain into
macrostress. A new theory allows the calculation of diffraction
elastic constants for arbitrary symmetry both of crystallites
and specimen. The theory makes use of the equivalent inclusion
method as well as of the solution of the anisotropic inclusion
problem, and it assumes that the crystallite shape can be considered
as, on average, spherical. The formalism can be applied in a very
transparent way to any kind of aggregate containing crystallites.